Apparatus for mixing fluids



March 27, 1956 F. E. DAVIS 2,739,884

APPARATUS FOR MIXING FLUIDS Filed Sept. 25 1953 2 Sheets-Sheet 1 F IEIl-Fmm f. flflV/f,

March 1956 F. E. DAVIS I 2,739,884

APPARATUS FOR MIXING FLUIDS Filed Sept. 25, 1953 2 Sheets-Sheet 21710672109! Ham 5 z74v/5,

United States Patent 9 APPARATUS FOR MIXING FLUIDS Floyd E. Davis, Gary,Ind., assignor to United States Steel Corporation, a corporation of NewJersey Application September 25, 1953, Serial No. 382,359

4 Claims. (Cl. 48-180) This invention relates to an improved device formixing fluids in relatively large conduits.

One purpose for which my device is especially suited is for introducingan enriching gas to another gas carried in a main. For example, blastfurnace gas has a relatively low calorific value (approximately 90 B. t.u. per cu. ft.), and before it is used for some purposes, it is enrichedby addition of gas of higher calorific value, such as coke oven gas(approximately 550 B. t. u. per cu. ft.). Such additions convenientlyare made in the blast furnace gas main, which may be feet or more indiameter. For proper utilization the gases must be mixed intimately toproduce a uniform product, and the calorific value of the product mustbe controlled carefully. Nevertheless it is apparent that the inventionis not restricted to this particular application.

An object of the invention is to provide an improved mixing device whichassures that the added fluid is mixed thoroughly with the fluid alreadyin the mixing space, and which facilitates controlling the amount offluid added.

A further object is to provide, in combination with a large diameterconduit, an improved fluid adding and mixing device which distributesthe added fluid over the full cross section of the conduit and thusenables this fluid to mix intimately into the fluid already in theconduit in a relatively short distance.

A more specific object is to provide, in combination with a largediameter conduit, an improved fluid mixing and adding device whichincludes a plurality of radial feeding pipes extending into the conduitin a common plane and spaced uniformly around its circumference, saidpipes having discharge openings facing in the upstream direction andbeing of an area proportioned to the area they serve in the conduit.

In accomplishing these and other objects of the invention, I haveprovided improved details of structure, a preferred form of which isshown in the accompanying drawings, in which:

Figure .l is a longitudinal section through a conduit equipped with amixing device embodying features of my invention;

Figure 2 is a cross section on line II-II of Figure 1;

Figure 3 is a longitudinal section on a larger scale on line III-III ofFigure l; and

Figure 4 is a cross section on a larger scale illustrating the differentzones in the conduit.

Figures 1 and 2 show a relatively large diameter fluid conduit 10, forexample a blast furnace gas main. The fluid travels in the directionindicated by the arrow in Figure 1. In accordance with my invention, aplurality of feeder pipes 12, in this instance six, extend through thewall of the conduit. These pipes are spaced uniformly around thecircumference of the conduit and they extend radially thereof andterminate adjacent the central axis. The axes of the pipes occupy acommon plane which is perpendicular to the axis of the conduit. Eachpipe 12 has a discharge slot 13 which faces in thfeupstream direction ofthe conduit; The" slots 13' extend These inner ends preferably taperandare closed, so that all discharge is throughtheslo'ts 13'. The" outeren'ds' of' the pipes 12 areconne'ctedto a supply line 14th'roughsuitable connecting pipes 15. The supply line carries a fluid to beadded to that in the conduit, for example coke oven gas.

To obtain proper mixing of the two fluids, the width of each dischargeslot 13 increases along its length outwardly from the central axis ofthe conduit 10. The change is such that the slot area remainsapproximately proportional to the cross sectional area of the portion ofthe conduit which it serves. In Figure 4 I have shown the cross sectionof the conduit divided into four concentric zones A, B, C and D. Theslot 13 is narrowest in the central zone A and becomes progressivelywider in steps in the zones B, C and D which have greater crosssectional area. Nevertheless it is apparent that equivalentproportioning could be obtained with uniformly tapered slots.

Since the slots 13 discharge upstream of the conduit 10, the flow ofadded fluid immediately adjacent these slots is counter to that of thefluid already in said conduit. Nevertheless the latter is much morevoluminous and it sweeps the added fluid around the pipes 12, somewhatas indicated in Figure 3. intimately, and a short distance beyond thepipes 12 the mixture becomes uniform. The mixture can be sampled at anylocation along the conduit after it has become uniform, and the amountof added fluid can be controlled through suitable valves in the supplyline 14 to furnish a mixed product of the desired composition.

While I have shown and described only a single em bodiment of theinvention, it is apparent that modifications may arise. Therefore, I donot wish to be limited to the disclosure set forth but only by the scopeof the appended claims.

I claim:

1. The combination, with a conduit of relatively large diameter andhaving upstream and downstream directions and being adapted to carry arelatively large volume of fluid in the latter direction, of a devicefor adding a relatively small volume of fluid to that already in theconduit comprising a plurality of uniformly spaced radial feed pipesextending into said conduit, said pipes having discharge openings facingin the upstream direction of said conduit counter to the direction offlow of fluid in the latter and being otherwise closed, said openingsfurnishing larger discharge areas adjacent the walls of said conduitthan adjacent the central axis, and means for introducing fluid to saidpipes, said conduit extending beyond said pipes in the downstreamdirection to allow the two fluids to form a uniform mixture therein.

2. A combination as defined in claim 1 in which said pipes extend fromthe walls of said conduit to adjacent the central axis thereof and theaxes of said pipes occupy substantially a common plane perpendicular tothe central axis of said conduit.

3. A combination as defined in claim 2 in which said discharge openingsare in the form of slots of increasing width outwardly from the centerof said conduit to proportion their area to that of the portion of saidconduit which they serve.

4. The combination, with a large diameter gas main having upstream anddownstream directions and adapted to carry gas of low calorific valuetoward the latter direction, of a device for adding an enriching gas ofhigher calorific value and intimately mixing the two gases immediatelybeyond the place of addition comprising a Consequently the two fluidsmix plurality of uniformly spaced radial pipes extending from the wallsof said main inwardly to adjacent the central axis thereof, said pipeshaving elongated continuous discharge openings facing in the upstreamdirection of said,

main counter to thedirection of flow of the gas of 10W calorific valueand being otherwise closed, said openings providing a greater dischargearea adjacent the Walls of said main than adjacent the central axis, andmeans for introducing an enriching gas to said pipes.

UNITED STATES PATENTS Great Britain Oct. 15, 1913

1. THE COMBINATION, WITH A CONDUIT OF RELATIVELY LARGE DIAMETER ANDHAVING UPSTREAM AND DOWNSTREAM DIRECTIONS AND BEING ADAPTED TO CARRY ARELATIVELY LARGE VOLUME OF FLUID IN THE LATTER DIRECTION, OF A DEVICEFOR ADDING A RELATIVELY SMALL VOLUME OF FLUID TO THAT ALREADY IN THECONDUIT COMPRISING A PLURALITY OF UNIFORMLY SPACED RADIAL FEED PIPESEXTENDING INTO SAID CONDUIT, SAID PIPES HAVING DISCHARGE OPENINGS FACINGIN THE UPSTREAM DIRECTION OF SAID CONDUIT COUNTER TO THE DIRECTION OFFLOW OF FLUID IN THE LATTER AND BEING OTHERWISE CLOSED, SAID OPENINGSFURNISHING LARGER DISCHARGE AREAS ADJACENT THE WALLS OF SAID CONDUITTHAN ADJACENT THE CENTRAL AXIS, AND MEANS FOR INTRODUCING FLUID TO SAIDPIPES, SAID CONDUIT EXTENDING BEYOND SAID PIPES IN THE DOWNSTREAMDIRECTION TO ALLOW THE TWO FLUIDS TO FORM A UNIFORM MIXTURE THEREIN.